Optimised formulation and characterisation of liposomes for enhanced stability and antiproliferative efficacy of <i>Orthosiphon aristatus</i> var. <i>aristatus</i> extract in lung cancer treatment

This study aimed to characterise and evaluate the antiproliferative potency of a standardised 50% ethanol extract of <i>Orthosiphon aristatus</i> var. <i>aristatus</i> leaves against human lung cancer cells <i>in vitro</i>. A liposomal drug delivery system was developed to enhance bioavailability and efficacy. Three formulations were designed with different extract-to-phospholipid ratios, phospholipid, and cholesterol content. NP2, formulated with a 1:1 extract-to-phosphatidylcholine ratio and 20% cholesterol, demonstrated optimal stability and efficacy. Liposomes were quantitatively and qualitatively characterised using light microscopy, TEM, SEM, zeta sizer, and zeta potential analysis. NP2 demonstrated better bioactive compounds release properties and better stability than the extract. The extract and liposomes inhibited the proliferation of human lung adenocarcinoma (A549) and normal endothelial cells (EA.hy926). The findings indicate that the extract possesses potent anti-lung cancer activity, with the NP2 liposomal formulation enhancing its therapeutic potential.